The present invention relates to a window winder device particularly adapted to be mounted on a motor vehicle door for controlling the vertical displacement of a movable window pane thereof.
Window winder devices known up to now have included those in which a slide, mounted so as to be slidable along a guide and connectible to a lower edge of the movable window pane, is displaced along the said guide by means of a flexible actuator member constituted by a metal cable about which there is helically wound a metal wire defining, about the said cable, a helical thread meshing with toothed drive means which can impart to and fro movements to the said metal cable within a fixed flexible cover the function of which is to prevent the said metal cable from deforming when subjected to compression forces.
The above described known window winder devices normally have the disadvantage of allowing the window to be lowered when a relatively low downward force is applied to it externally. This is due to the fact that any compression force applied to the window from the outside is converted into a compression force applied to the turns of the said helical metal wire at the point of coupling between these latter and the drive means. Since the sliding of the said turns toward one another along the metal cable corresponds to an increase in the diameter of the turns themselves, when the static friction has been overcome, these latter compress in the manner of a spring against one another freeing the window which can thus easily be lowered from the outside.
The above described known window winder devices, again because of the possible sliding of the turns of the said metal wire along the metal cable, can easily become jammed since the pitch of the said helical wire can easily not correspond to the pitch of the said toothed drive means.